Elastic-fluid turbine.



R. N. BHRHART.

ELASTIC FLUID TURBINE. APPLICATION Mum MAY 16, 1906.

I: L Q r N kg INVENTOR. By w Mom\ I.

ATTORNEY.

Patented Au 30, 1910.

3 SHEETS-SHEET 1.

R. N. EHRHART. ELASTIC FLUID TURBINE. APPLIOATION FILED MAY 18, 1906. 968,840. Patented Aug. 30, 1910.

3 SHEETS-SHEET 2.

WITNESSES: INVENTOR.

BY ML R. N. EHRHART. ELASTIG FLUID TURBINE. APPLIOATION rum) MAY 16,1908.

968,840. Patented Aug. 30,1910.

3 SHEETS-SHEET 3.

\ ATTORNEY.

UNITED STATES PATENT orrron.

RAYMOND N. EHRHART, 0F PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THE WEST- INGI-IOUSE MACHINE COMPANY, A CORPORATION OF PENNSYLVANIA.

To all whom it may concern.

Be it known tlfiti; I, RAYMOND N. Enn- HART, a citizen of the United States, and a resident of Pittsbur in the county of Allegheny and State of l ennsylvania, have made a new and useful Invention in Elastic-Fluid Turbines, of which the following is a specifi: cation.

This invention relates to elastic fluid turbines and has for an object the production of a turbine in which improved mcansare utilized for balancing the longitudinal or axial thrust of the rotor element.

In elastic fluid turbines of the axial flow and multi-cellular types, considerable longitudinal or axial thrust of the rotor element is encountered, which is due to the longitudinal pressure of the elastic fluid on the working and ex )osed surfaces of the rotor. Considerable di culty is encountered and expense incurred in constructing balancing dummies or pistons for the rotor element and in providing a system of fluid chambers and passages, which, in conjunction with the dummies or pistons, are arranged to counterbalance the longitudinal thrust of the rotor element by an equal and opposite thrust. of the dummies or pistons.

I am aware that it has been proposed to, obviate the balancing diiiiculties encountered by dividin' one stage of the turbine into two sections of equal diameter, which are located at opposite ends of the turbine rotor and through which the motive fluid [lows in opposite directions. I am also aware that it has been proposed to locate the separate sections of the divided stage at one end of the turbime and to so proportion the diameters of the sections that the rotor will be balanced for certain loads, steam pressures and degrees of vacuum, and, while the object of my invention is the production of a turbine in which a stage thereof is divided into two sections for the purpose of balancing, I claim only a specific arrangement .of parts in which the separate sections of the divided stages are of different diameter but so proportioned and arranged that the turbine is balanced for all loads.

According to my invention, the turbine is divided in'to high and low pressure stages. The blacling oi the high pressure stage or Stages is mounted on drums or equivalent members in the usual manner; th blading and the fluid passages of the low pressure Specification of Letters Patent.

Application filed May 16,

ELASTIC-FLUID TURBINE.

Patented Aug. 30, 1910.

1906. Serial No. 317,135

stage are, however, so arranged that the fluid exhausted from the high pressure stage or stages and entering the low pressure stage is'divided into two parts and the separate parts caused to flow in opposite directions while traversing the working passages. The working passages are so arranged an the exposed surfaces so proportioned that the axial or longitudinal thrust exerted on the rotor element in the low pressure stage by one part of the motive fluid is balanced by an equal and opposite axial thrust exerted by the other part of the motive fluid.

In the drawings accompanying this application and forming a part thereof, Figure 1 is a longitudinal section of a turbine embodying my invention; Fig. 2 is a longitudinal section of a 'turbine embodying a modification of my invention; and Fig. 3 is a longitudinal section of a turbine embodying a still further modification.

Referring to Fig. 1 A rotor 4, which coinprises an initial or high pressure section 5, an intermediate section 6 of increased diamcter and a final or low pressure section 7, is mounted on shafts 8, which are journaled in suitable bearings, (not shown). A casing 9, divided on the horizontal plane which passes through the axis of the rotor, as is now conunon, incloses the rotor and its inner surfaces are so formed that fluid chambers and passages of the proper sectional ing through casing 9, communicates with an annular chamber 12 formed between the casing and the surface of the rotor, and which communicates with the initial or high pressure stage of the turbine.

The initial or high pressure stage comprises alternate rows of directing vanesi13 mounted on the casing and working blades 14 mounted on the section 5 of the rotor. The blades and vanes are so formed and arranged that the motive fluid in passing through the initial section is fractionally expanded and the resulting kinetic energy, of the fluid, imparted to the moving blades by impact and reaction.

'lhe motive fluid discharged from the initial stage enters an annular chamber 15 which communicates with an intermediate stage, the moving blades of which are mounted on thesection 6 of the rotorand the vanes on the casing 9. The motive fluid discharged from the intermediate stage en- 'ters an' annular chamber 16 from which it is led into the final or low pressure stage.

The low pressure stage is divided into two sections 17 and 18, through which the motiy'e fluid flows in opposite directions. The section 17 communicates directly with the chamber 16 and comprises alternate rows of stationary vanes, which are mounted on the casing, and moving blades, which are mounted on a" drum I9 carried by the rotor element 4. The section 18 comprises alternate annular rows of vanes, mounted on an annular flange 21, formed integrally with and extending into the casing 9, and moving.

" blades, mounted on aportion of the drum tiona 19 of reduced diameter. The blades and vanes of section 18 receive motive fluid from the chamber 16 through a passage 22 formed between the drum l9 and its mounting member. Both sections, 17 and 18, of the low pressure stage discharge the motive'fiuid passing through them into an exhaust passage 23,

.Which communicates with the atmosphere or .a condenser through an exhaust port 24,

formed in the casing 9. The blades and vanes of both sections of the l w pressure stage are adapted to fracily expand the motive fluid and abstract, by impact and reaction, the velocity energy rendered available by the partial expansions.

The intermediate section 6 of the rotor element'is of greater diameter than the initial section fi and the rotor element therelongitudinal thrust on the exposed surface of ranged to restrict and check the flow of fore, provided with a balance piston or dummy 25, which is located contiguous with .and ex osed to the pressure within an aunularc ialnber 26, formed between the rotor and the stationary casing. The chamber 26 communicates with the chamber 15 through a conduit 27 and the arrangement is such that the motive fluid conducted from the chamber 15 to the chamber 26 will exert a the piston 25 equal and opposite to the axial thrust exertedby the motive fluid on the exposed surfaces, of the intermediate tion 6.

The axial or longitudinal thrust exerted by the motive fluid in passing through the initial stage is balanced by a piston 28 so formed on .the rotor that its effective balanc- 5E fluid. in the chamber 11.

ing face is exposed to the pressure of the The pistons 28 and 25- are provided with labyrinth or other packings, which are ar- ,mOt1Ve fluid between the peripheral faces ofthe pistons and adjacent faces of the casing.

The end 31 of the rotor element, which is exposed. (through the passage 22) to the fluid pressure in the chamber 16, is so proecaaao portioned that it, in conjunction with the exposed lateral surfaces of the Working section 18, counterbalances the longitudinal thrust of the motive fluid on the annular face 32 of the drum 19 and .the exposed Working surfaces ofthe section ,17. The annular face 33 of the drum 19, which is exposed to exhaust pressure, is equal to the face 34 of the piston 25, which isalso exposed to the exhaust pressure as transmitted to a chamber 35 through a,con'duit 36, which communicates with the exhaust passage. 23. With such an arrangement the rotor element is balanced for all loads, fluid pressures and degrees of vacuum. It is apparent that the area of the annular face 331s equal to the face 34 of the piston 25, since the effective diameter of the piston 25 is e ual to. the diameter of the section 6 and the ads 31 of the rotor element is made equal to the annular face 32. This may be made more apparent from the following equations:

J A=B I A+C=:B+C where A equals the area of the face-.31; B

the area of the face 32; and C the difference in areas between the faces 32 and 33. From' the drawings, it is evident that A+C equals the area of the face 34 of the dummy piston 25 and B-l-Cequals the area-of the face 33, and SlIlCQiA. was made equal to B, the faces 33 and 34 are equal to each other.

In Fig. 2 a modification of the invention a is shown. The passage 22,-whicli isupplies motive fluid to the section 17 of the lowpressure stage, is supplied with motive fluid from a chamber 38, located with the intermediate stage of the turbine.

In Fig. still another modification is shown; theturbineillustrated is provided with an intermediate stage divided into two sections 39 and 40 of different diameters, be-

the shaft, since the chamber 35 1s exposed-t0 vacuum pressure and the chamber 42, at'

the other end of the turbine, is exposed to approximately atmospheric pressure. when the turbine is running "condensing and. ordinary steam pressures are utilized.

Iii-accordance With the provisions of the patent statutes, I have described the principles of operation of my invention together with the apparatus-I now consider. to represent the best embodiment thereof; but I desire it to be understood that the apparatus shown is only illustrative and that varlo'us changes may be made and still fall within the spirit and scope of my invention.

What I claim is:

- 1. In combination in an elastic fluid turbine, a rotor, provided with a balance pis ton, located at the initial end of said turbine and a bladed piston, located at the exhaust in (parallel with said first mentioned. piston end of said turbine, of less diameter than said balance piston.

2. In combination in an elastic fluid turbine,a rotor, provided with a plurality-of balance pistons, at the initial end of said turbine and a bladed piston'at the exhaust end of said turbine of less diameter than the largest of said balance pistons.

3. In combination in an elastic fluid turbine, a rotor, comprisin a bladed piston, located at one end of said turbine, a balance piston, a second bladed piston, intermediate of said first mentioned bladed piston and said balance piston, of larger diameter than the first mentioned piston and a fluid passa e extending through said rotor between said bladed plstons.

4. In combination in an elastic fluid turbine, a rotor, comprising a bladed piston, located at one end of said turbine, a balance piston, a second bladed piston of larger diameter than the first mentioned piston and j a fluid passage extending through said ro-. tor between said bladed pistons. i

5. In an elastic fluid turbine, a working stage through which the fluid flows in one direction only and a divided low pressure stage comprising sections of different diameters through which the fluid flows in opposite directions and means for balancing said first mentioned working stage.

6. In an elastic fluid turbine, a working stage throu h which the,fluid flows in one direction on y, a divided low pressure stage, comprising sections of different diameters, through which the fluid flows in op osite direction located'at one end of sa1 turbine and means for balancing said first mentioned working stage.

7. In ari'elastic fluid turbine, a rotor, comprizicng a bladed piston, a balance piston and a s ond bladed piston of smaller diameter Located atthe low pressure end of said turine.

Im an elastic fluid turbine,'a rotor, comprising a bladed piston, a balance piston and a second bladed piston of smaller diameter located at the low-pressure end of said turbine.

9. -In an elastic fluid turbine, the combination of-a bladed spindle comprising a pluralitybi stepsai d a plurality of pistons for balancing theen'd thrust of allbut one of said steps and a bladed piston at one end of said rotor of less diameter than the largest of said steps.

10. In an elastic fluid turbine, the combination of a bladed spindle comprising a plurality of steps and a plurality of pistons for balancing the end thrust of all but one with reeutrant inner walls, the inner peripheral faces of which are rovided 'with stationary directing vanes, an a bladed piston surrounded by said re'ntrant walls and cooperating therewith. I

13. In combination in an elastic fluid turbine, a high, intermediate and low pressure stage; an axial flow section of less diameter than any of the afore-mentioned stages and comnmnicating with the exhaust of the turbins and receiving fluid from the intermediate stage for balancing the longitudinal thrust of the low pressure stage.

14. In an elastic fluid turbine, high, intermediate and low pressure sections, balance pistons for, said high and intermediate pressure sections, and a section located adjacent to said low pressure section, receiving fluid from said intermediate section and in which the inlet pressure is higher than the inlet pressure of said low pressure section.

15. In an elastic fluid turbine, high, intermediate and low pressure sections, a balance section for said low pressure section located adjacent thereto and communicating with said intermediate section between the inlet and exhaust thereof.

16. In combination in an elastic fluid turbine, a high, intermediate and low pressure stage, an axial flow section communicating with the exhaust of the turbine and receiving motive fluid from a point intermediate of the intermediate stage for balancing the longitudinal thrust of the lowpressure stage.

17 In combination in a turbine, high, intermediate and low pressure stages of progressively increasing diameters, a balanced piston for the high and intermediate stages and a working section of less diameter than the low pressure section, receiving motive fluid from a point intermediate of the intermediate stage for balancing the longitudinal thrust of the low pressure stage.

18. In combination in a turbine, high, intermediate and low pressure stages of pro gressively increasing diameters, a balanced piston for the high and intermediate stages and a working section of less diameter than the low pressure section, receiving motive fluid through the turbine rotor from a point intermediate of the intermediate stage for balancing the longitudinal thrust of the low pressure stage.

19. Inan elastic fluid turbine, a rotor element comprising a bladed piston located git one end of said turbine, a balance piston 10- cated at the otherend of said turbine, and a second-bladed piston'oflarger diameter than said first mentioned bladed piston located intermediate thereof and said balance piston. i

20. In an elastic fluid turbine, a. working section located at one end-of said turbine, a balance piston located at the other end of said turbine, and a second working section 21. A turbine having an exhaust chamber with a rentrant inner wall, the inner pel 1906. of larger diameter than'the first section, 16-

. ceted intermediate of said piston and said section.

wall, the inner peripheral faces of which are provided with fluid directing means, and a bladed piston surrounded by said well and cotiperating therewith.

In testimony whereof, I have hereunto subscribed my name this 14th day of May,

RAYMOND 'EHRHART.

Witnesses: I

CHARLES W. MCGHEE, E. W. McGALIJsTnR. 

